Evaluation of The Psychometric Properties of The Turkish Version of The Brief-Caffeine Expectancy Questionnaire (B-CaffeQ): An Adaptation Study in Recreationally Active Individuals

INTRODUCTION

Caffeine (1,3,7-trimethylxanthine) is most commonly found in coffee as the main pharmacologically active ingredient. In general, brewed coffee has the highest content among foodstuffs containing caffeine. Coffee (230-250ml), depending on the preparation method, the type of beans, roasting, grinding type and brand, contains 35-250 mg of caffeine while tea (150 ml) 24-50 mg, cola drinks (180 ml) 15-30 mg, cocoa (150 ml) 2-7 mg, chocolate (28 g) 1-36 mg, and the foods containing chocolate mostly contain less than 15 mg caffeine.

Doses of up to 300-400mg per day in healthy adults (19 and over) are specified as safe upper limit without any harmful effects. This amount corresponds to 4-5 cups of medium coffee. However, it is stated that caffeine consumption equal to 6 cups of dark coffee generally does not cause any side effects. It is stated that the daily limit for adolescents and children is 100 mg and this limit should not be exceeded. However, coffee is not the only source of caffeine, and other sources caffeine consumed should also be taken into account.

The average daily caffeine consumption in Turkey for adolescents and children aged 15 and below is an average of 197 mg and 202 mg for 18 and older. The source of caffeine for adolescents is mostly tea, carbonated soft drinks and instant coffee consumption. Average daily caffeine consumption in adult working individuals is 247 mg, and this is due to the consumption of carbonated soft drinks, chocolate, instant coffee, respectively. It is seen that 20% of university students who consume caffeine have an average daily consumption of 250 mg and above, and this mostly due to the consumption of tea, coffee, Turkish coffee, carbonated soft drinks and chocolate. In USA, while the main source of caffeine is coffee for the age of 18 and above, it is caffeine-containing soft drinks for the age of 2-17.

There is evidence that some individuals' expectancies of caffeine's effects on physical performance and mood may affect the magnitude of these effects. There are studies showing that caffeine anticipation effect affects mood, attention, and vitality. In the case of caffeine expectancy, placebo administration stimulates changes in the dopaminergic system in the brain. The neurobiological mechanisms of caffeine and placebo caffeine were similar in the brain, but somewhat more limited in placebo caffeine. It is stated that the expectancy of the individual may manage the placebo effect and accordingly, the expected effect of caffeine or the drug consumed may change the response to placebo. Beyond the pharmacological effects of a drug, an individual's expectancies of it may also contribute to the intensive experiences of the drug in question. The fact that individuals who are told they had decaffeinated coffee but are given caffeine perform worse than those who do not consume caffeine, support the view that the pharmacological effects of caffeine act synergistically with anticipation. In addition, it has been stated that the effects caused by caffeine withdrawal may also be caused by the negative expectancies (nosebo) of an individual. These results provided evidence that the subjective and behavioral effects of caffeine consumption may be positive or negative depending on the individual's expectancies from caffeine. These expectancies may arise from the individual's previous experiences with caffeine. The effects of caffeine depend on the individual's expectancies, so if the individual consumes a beverage expecting that it has caffeine in it, these expectancies may be generalized as placebo conditions. In placebo studies, it is stated that one of the factors that cause an individual to respond to a treatment may be caused by the type of individual who may respond to treatment via expectancies. In other words, this view is not specific to the treatment of the practice applied, rather that the response may be shaped according to the expectancies of the individual, that expectancies may cause a placebo (or nosebo) effect. When there is confidence in the drug effect of a drug in a particular activity, an expectancy of a specific behavioral effect of that drug may also be formed. Based on expectancies about the effects of caffeine, the behavioral response to this drug derivative can be predicted. However, this expectancy theory is insufficient to explain the fact that some individuals without expectancies not showing stimulating effects when they consume caffeine for the first time. There are other studies which do not observe expectancy affects in caffeine consumption, suggesting placebo and expectancy effects are caused by introspection. The results showed that both pharmacological and expectancy factors affect the actual and expectancy effects of caffeine in an individual's behaviour.